A modification of the LENS (Low Energy Neutrino Spectroscopy) project for spectroscopy of solar neutrinos with energies above about 715 keV on the basis of new technologies and solutions is examined. ...The respective detector employs
In nuclei as a target for neutrinos. The creation of a detector containing about 200 t of a scintillator loaded with 10 t of indium will make it possible to measure, within five years, the energy spectra of solar neutrinos from
Be, neutrinos from the CNO cycle, and
neutrinos with small systematic errors. The detector was simulated in the form of a set of cells of a liquid scintillator doped with indium (about 10
in weight). Necessary technical conditions for detector cells are formulated, and the possible counting rate for events induced by internal and external backgrounds and characterized by an energy release of 600 to 1600 keV is estimated. It is shown that such a detector is implementable, in principle.
Low background segmented liquid scintillator detector, doped with an indium as a target for solar neutrino registration, can be used for measuring total solar neutrino spectrum including
neutrinos. A ...detector consisting of small modules filled with liquid scintillator in the volume of 1–2 L is considered. Silicon matrices are used for light collection. The background of indium beta-activity is suppressed by triple coincidences. The detector of such a type can measure
Be neutrino flux with high accuracy and independently check the measurement performed by the Borexino Collaboration.
The energy resolution is calculated for a neodymium-containing liquid organic scintillation detector (Nd-OS) with a volume of several liters to search for neutrinoless double beta decay of
150
Nd as ...a function of the neodymium concentration up to 5 g/L. The results are presented in detailed tables and graphs.
Upgrade for Phase II of the Gerda experiment Agostini, M.; Bakalyarov, A. M.; Balata, M. ...
European physical journal. C, Particles and fields,
05/2018, Letnik:
78, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The
Gerda
collaboration is performing a sensitive search for neutrinoless double beta decay of
76
Ge
at the INFN Laboratori Nazionali del Gran Sasso, Italy. The upgrade of the
Gerda
experiment from ...Phase I to Phase II has been concluded in December 2015. The first Phase II data release shows that the goal to suppress the background by one order of magnitude compared to Phase I has been achieved.
Gerda
is thus the first experiment that will remain “background-free” up to its design exposure (
100 kg
year
). It will reach thereby a half-life sensitivity of more than
10
26
year within 3 years of data collection. This paper describes in detail the modifications and improvements of the experimental setup for Phase II and discusses the performance of individual detector components.
Because of a high energy of the neutrinoless double-beta decay (0
ν
2
β
) of the isotope
150
Nd and a high value of the daughter-nucleus charge
Z
f
,
150
Nd is one of the most promising isotopes for ...0
ν
2
β
-decay searches. A
150
Nd-containing detector on the basis of a liquid organic scintillator permits employing large isotope masses. Requirements on the radiation purity of the neodymium sample used are determined. The possible design of a large-scale detector of this type and expected results are considered.
Modeling of GERDA Phase II data Agostini, M.; Bakalyarov, A. M.; Balata, M. ...
The journal of high energy physics,
03/2020, Letnik:
2020, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A
bstract
The GERmanium Detector Array (Gerda) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double-beta (0
νββ
) decay of
76
Ge. The technological ...challenge of Gerda is to operate in a “background-free” regime in the region of interest (ROI) after analysis cuts for the full 100 kg
·
yr target exposure of the experiment. A careful modeling and decomposition of the full-range energy spectrum is essential to predict the shape and composition of events in the ROI around
Q
ββ
for the 0
νββ
search, to extract a precise measurement of the half-life of the double-beta decay mode with neutrinos (2
νββ
) and in order to identify the location of residual impurities. The latter will permit future experiments to build strategies in order to further lower the background and achieve even better sensitivities. In this article the background decomposition prior to analysis cuts is presented for Gerda Phase II. The background model fit yields a flat spectrum in the ROI with a background index (BI) of
16.04
−
0.85
+
0.78
·
10
−
3
cts/(keV
·
kg
·
yr) for the enriched BEGe data set and
14.68
−
0.52
+
0.47
·
10
−
3
cts/(keV
·
kg
·
yr) for the enriched coaxial data set. These values are similar to the one of Phase I despite a much larger number of detectors and hence radioactive hardware components.
Pulse shape analysis in Gerda Phase II Agostini, M.; Araujo, G.; Bakalyarov, A. M. ...
The European physical journal. C, Particles and fields,
04/2022, Letnik:
82, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The GERmanium Detector Array (
Gerda
) collaboration searched for neutrinoless double-
β
decay in
76
Ge using isotopically enriched high purity germanium detectors at the Laboratori Nazionali del ...Gran Sasso of INFN. After Phase I (2011–2013), the experiment benefited from several upgrades, including an additional active veto based on LAr instrumentation and a significant increase of mass by point-contact germanium detectors that improved the half-life sensitivity of Phase II (2015–2019) by an order of magnitude. At the core of the background mitigation strategy, the analysis of the time profile of individual pulses provides a powerful topological discrimination of signal-like and background-like events. Data from regular
228
Th calibrations and physics data were both considered in the evaluation of the pulse shape discrimination performance. In this work, we describe the various methods applied to the data collected in
Gerda
Phase II corresponding to an exposure of 103.7 kg year. These methods suppress the background by a factor of about 5 in the region of interest around
Q
β
β
=
2039
keV, while preserving
(
81
±
3
)
% of the signal. In addition, an exhaustive list of parameters is provided which were used in the final data analysis.
The ability to detect liquid argon scintillation light from within a densely packed high-purity germanium detector array allowed the
Gerda
experiment to reach an exceptionally low background rate in ...the search for neutrinoless double beta decay of
76
Ge. Proper modeling of the light propagation throughout the experimental setup, from any origin in the liquid argon volume to its eventual detection by the novel light read-out system, provides insight into the rejection capability and is a necessary ingredient to obtain robust background predictions. In this paper, we present a model of the
Gerda
liquid argon veto, as obtained by Monte Carlo simulations and constrained by calibration data, and highlight its application for background decomposition.
Calibration of the Gerda experiment Agostini, M.; Araujo, G.; Bakalyarov, A. M. ...
European physical journal. C, Particles and fields,
08/2021, Letnik:
81, Številka:
8
Journal Article
Recenzirano
Odprti dostop
The GERmanium Detector Array (
Gerda
) collaboration searched for neutrinoless double-
β
decay in
76
Ge with an array of about 40 high-purity isotopically-enriched germanium detectors. The ...experimental signature of the decay is a monoenergetic signal at
Q
β
β
=
2039.061
(
7
)
keV in the measured summed energy spectrum of the two emitted electrons. Both the energy reconstruction and resolution of the germanium detectors are crucial to separate a potential signal from various backgrounds, such as neutrino-accompanied double-
β
decays allowed by the Standard Model. The energy resolution and stability were determined and monitored as a function of time using data from regular
228
Th calibrations. In this work, we describe the calibration process and associated data analysis of the full
Gerda
dataset, tailored to preserve the excellent resolution of the individual germanium detectors when combining data over several years.
Alpha backgrounds in the AMoRE-Pilot experiment Alenkov, V.; Bae, H. W.; Beyer, J. ...
European physical journal. C, Particles and fields,
12/2022, Letnik:
82, Številka:
12
Journal Article
Recenzirano
Odprti dostop
The Advanced Mo-based Rare process Experiment (AMoRE)-Pilot experiment is an initial phase of the AMoRE search for neutrinoless double beta decay of
100
Mo, with the purpose of investigating the ...level and sources of backgrounds. Searches for neutrinoless double beta decay generally require ultimately low backgrounds. Surface
α
decays on the crystals themselves or nearby materials can deposit a continuum of energies that can be as high as the
Q
-value of the decay itself and may fall in the region of interest (ROI). To understand these background events, we studied backgrounds from radioactive contaminations internal to and on the surface of the crystals or nearby materials with Geant4-based Monte Carlo simulations. In this study, we report on the measured
α
energy spectra fitted with the corresponding simulated spectra for six crystal detectors, where sources of background contributions could be identified through high energy
α
peaks and continuum parts in the energy spectrum for both internal and surface contaminations. We determine the low-energy contributions from internal and surface
α
contaminations by extrapolating from the
α
background fitting model.
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